1. Field of the Invention
This invention relates to shaft bearing retention means and is particularly advantageous for use with large-diameter shafts and shafts wherein a threaded clamping nut cannot be passed over the shaft.
Heretofore it has been the practice to provide a threaded clamping ring, or nut, for the purpose of retaining a bearing assembly or a rotor hub on a large-diameter shaft. There are several disadvantages to this construction. Helicopter rotor drive shafts, for example, are relatively thin walled hollow shafts and when threaded such a shaft has a high stress concentration at the threaded section. Also threading a large-diameter shaft is expensive, requiring special manufacturing and inspection tools. Further, having to pass a nut over a long shaft limits design flexibility.
2. Prior Art Patents
U.S. Pat. No. 250,088, issued Nov. 29, 1881 to A. Loehner shows a shaft hanger and box having conical shaft supporting rings m which are retained in position by a single piece retainer I. The radial clamping force exerted on the shaft by conical rings m is varied by turning bolts r which attach the aforementioned retainer I to a rigid support which has a conical surface corresponding to the conical rings m. The rings m are not segmented, however, and do not engage a conical indentation in the shaft to produce axial thrust.
U.S. Pat. No. 903,280, issued Nov. 10, 1908 to G. P. Youmans shows a pipe coupling in which a segmented flange 5 is retained about a pipe by a single retaining ring, or hoop 2.
U.S. Pat. No. 2,683,613, issued July 13, 1954 to O. V. Streed, Sr. et al shows a pipe coupling comprising two segmented flanges having a conical surface on their inner peripheries corresponding to similar surfaces on the outer surfaces of adjacent pipe sections. The two flanges are bolted together.
U.S. Pat. No. 3,112,941, issued Dec. 3, 1963 to W. J. Dutton, shows a rotor shaft and hub with a threaded nut on the shaft for holding the hub in which the hub and shaft have conical surfaces and clamping bolts on the nut cooperate with the conical surfaces to clamp the hub to the shaft. This construction does not eliminate the threaded nut.
The above prior art patents are made of record because they show elements of the bearing retention means of the present invention used in different but somewhat related arts.